Carpal tunnel syndrome is a common ailment of near epidemic proportions. Carpal tunnel syndrome results from compression of the median nerve. The median nerve extends down the arm, through the wrist and then branches into the hand, supplying the thumb, forefinger, middle finger and half the ring finger with nerves (the first through fourth metacarpals respectively). The portion of the wrist through which the median nerve extends is known as the carpal tunnel. The carpal tunnel is formed by the concave arch of the carpal bones and is roofed, on the palm side, by the transverse carpal ligament. Together, the carpal bones and the transverse carpal ligament form a relatively rigid compartment through which nine finger tendons and the median nerve must pass.
Synovial membranes serve as tissue lining surfaces that secrete synovial fluid to lubricate the tendons for smooth operation. When irritated or inflamed, these synovial membranes over produce synovial fluid and begin to swell. Eventually, the swelling begins filling the space of the carpal tunnel and compresses the relatively soft tissue of the median nerve. In the early stages, this condition results in pain, numbness, tingling and a weakness of the fingers and thumb especially at night and on awakening. In more severe cases, the condition progresses to a loss of feeling, loss of grip and possibly even loss of some hand function.
Carpal tunnel syndrome may be caused by a number of factors including chronic diseases such as rheumatoid arthritis and diabetes mellitus, congenital defects such as anomalous muscles, acute trauma, age, birth control pill usage and pregnancy. Many occupations requiring repetitive motion also induce the ailment. For example, repeated and forceful up and down motions of the wrist cause finger tendons to rub over and across carpal tunnel structures (i.e. carpal bones and transverse carpal ligament). This rubbing irritates the tendons which, as described above, promotes over production of synovial fluid and swelling that eventually puts pressure on the median nerve inside the tunnel. Tasks requiring sustained or repeated stress over the base of the palm such as often occur when utilizing screwdrivers, scrapers and buffers also significantly raise the risk of suffering from the ailment. In fact, this ailment is now recognized by the government as being a major contributor to lost productivity.
Early identification of carpal tunnel syndrome allows the utilization of conservative treatment techniques. Such techniques include improvements in work area ergonomics to relieve the stresses that irritate and inflame the synovial membranes that swell and close the carpal tunnel. A splint may also be fitted to the wrist to hold the wrist in a functional position and prevent the wrist from being placed in extension and flexion.
In more severe cases, surgery may be necessary to release the transverse carpal ligament and open the carpal tunnel. More particularly, surgery consists of incising the transverse carpal ligament of the wrist and then placing the wrist in a splint for a short time to allow healing. As stiffness and pain often develop following surgery due to what is known as "sympathetic dystrophy", prolonged therapy is often necessary before an individual is able to return to work following such surgery. This therapy is specifically designed to restore strength and flexibility to the wrist and fingers with a goal of increasing flexibility and grip strength at least to that provided before the surgery and existence of the ailment.
In the past, such therapy has often consisted of wearing a wrist splint, as mentioned above, and completing squeezing exercises utilizing a soft rubber ball. In some instances, hand flexibility and finger spread are reestablished by taping small balls between the fingers to hold them in a spread position overnight. None of the prior art treatment procedures known to the applicant address increasing the suppleness of the hand, including the bones, tendons and muscles, to aid in treatment during the actual stretching procedure. Accordingly, in many cases, the patient is slow to respond to such a treatment procedure. Thus, the procedure has only met with limited success. A need is, therefore, identified for a new apparatus and method of providing hand therapy to aid in recovery from carpal tunnel syndrome.